Peter Capaldi had appeared on the show in a completely different role before being cast as the 12th Doctor, but Colin Baker did too in the original, so this is not the first an actor playing the Doctor had previously appeared as a different character on the show. Coincidentally, Capaldi appeared in the episode in which Karen Gillan had a different role before being cast as a full-fledged companion, Doctor Who: The Fires of Pompeii (2008).

When the first series was being made, television pirates were desperate to acquire the preview tapes. One of the people in the office had the idea of labeling the tapes with the anagram "Torchwood" rather than "Doctor Who", as a security measure to disguise the tapes when they were delivered from Cardiff to London. Writer Russell T. Davies liked this idea so much that it later inspired him to use it as a title when creating the spin-off series, Torchwood (2006).

The BBC considered ending the revived series at the end of David Tennant's tenure as The Doctor and the BBC questioned if the series could go on without David Tennant, whom had become a national treasure with his performance as The Doctor. But outgoing producer Russell T. Davies advised the BBC that it should not end and that it should keep on going.

Benedict Cumberbatch was rumored to be in line to play The Eleventh Doctor, however both he and Steven Moffat confirmed that the rumor was untrue, and that he was never under consideration for the role. Cumberbatch also stated that he had no interest in playing the role.

Producer Russell T. Davies had Christopher Eccleston's name on a shortlist for the role of the Doctor but didn't really think that he would accept the role. Davies soon received an email from Eccleston asking if he could audition for the part.

At first the estate of Terry Nation refused permission for them to use Daleks in the show (Terry Nation held copyright over the Daleks). One of the reasons they refused permission was because of the BBC granting permission for the Daleks to be used in Looney Tunes: Back in Action (2003). Huge fan of Doctor Who Steve Martin, who was the one who insisted Daleks be used in the movie, heard about the news and wrote a letter of apology to the Terry Nation estate and upon receiving it, the Terry Nation estate granted permission.

Peter Davison has said he considers this series an improvement on the original, not only because of its budget and digital effects but also because the series is produced by a writer, unlike the original series, which was always produced by a BBC staff producer. Davison has said that Rose, played by Billie Piper, was the first properly developed companion in the history of the series, and he expressed admiration for the sexual frisson and tension which was previously disallowed between the Doctor and his companions.

On Thursday 31 March 2005, the day after the show was picked up for a second series, the BBC Press Office announced that Christopher Eccleston was quitting the show, citing a fear of being typecast and long working hours as reasons for his departure. The BBC later apologized for issuing this statement, as they had done so without consultation with Eccleston. In fact it was agreed by mutual consent some months earlier that Eccleston would only do one series, with the BBC holding off announcing the news until after the series was finished. This would have allowed the regeneration of Eccleston's Ninth Doctor in episode 13 to be a surprise for the audience. Unfortunately, the BBC Press Office jumped the gun under pressure from the British Press who were concerned that a second series had been announced, but it had not been confirmed that Eccleston was returning. Fan reaction to Eccelston's departure was violent and the debate reached such a fever pitch that Outpost Gallifrey, the biggest Doctor Who fan site on the Internet, was forced to close down its forum for days.

A potential spin-off, "Rose Tyler: Earth Defence", was proposed in 2006, but did not progress beyond the idea stage, partly because Billie Piper did not want to return to the role, partly because Russell T. Davies realized that it would render the goodbye between The Doctor and Rose at the end of season 2 meaningless.

When Peter Capaldi was chosen as the 12th Doctor, he became the first Oscar winner to play The Doctor (though not for acting), the third Scottish actor (after Sylvester McCoy and David Tennant), the third actor to be older than the actor they replaced, and also (joint with the First Doctor William Hartnell) the oldest actor to be cast in the role since the very beginning of the series.

For the first series, producers were fearful of alienating new audiences with references to the original show, such as names and events, so such things were kept to a very bare minimum until audiences adjusted to the mythology. Even the first journey to another planet beyond Earth didn't take place until series two, which is unusual considering the universe-trotting nature of the original series.

Russell T. Davies did not audition any actors for the role of the Tenth Doctor, as he had recently finished working with David Tennant and believed him to be perfect for the role. Tennant was first approached about the possibility of playing the Tenth Doctor at a screening of 'Rose' at Davies' house on 23 March 2005. Contrary to fan-invented rumors, Tennant was never considered for the role of the Ninth Doctor.

Except for obvious scenes, most of the location shots are done in Cardiff, Wales in place for London. The one episode set in Cardiff, "The Unquiet Dead," was filmed in Swansea, mainly due to the fact that no buildings currently in Cardiff were built during that episode's time, 1869. Aside from this, Cardiff is the home of "Torchwood 3", which is featured in the episode "Last of the Time Lords".

Hugh Grant was once approached to play the Doctor. He turned down the role, thinking the show would not take off. He expressed deep regret in 2007 after seeing how successful the show had become. He did go on to play the Doctor in a sketch for Comic Relief.

Several episodes begin with the exact same sequence: a view of the earth's moon, then panning towards earth followed by a fast zoom down to London. Episodes in which this opening was used include "Rose", "The Christmas Invasion", "Army of Ghosts" and "The Runaway Bride".

On Saturday 5 March 2005 (some three weeks before its TV debut), a rough-cut version of episode one, "Rose" was leaked onto the Internet by an unnamed employee of a third-party contractor to CBC in Canada. The person responsible had their employment immediately terminated. The version is mostly similar to the broadcast version - the most notable difference is that instead of using Murray Gold's new version of the theme song, a remixed version of the original was used instead

This series is a direct continuation of the 1963-1989 series, rather than a reboot, reimagining or "next generation" style follow-up. The BBC decided to reset the series numbering at 1 for 2005, rather than call it Series 27, however fans informally refer to the seasons by the higher number.

In an acting master class at the Theatre Royal Haymarket in July 2011, Christopher Eccleston expanded the reasons for his leaving the show. He cited creative differences with "the senior people" on the production and stated he did not like "the culture" of working on the production.

Penelope Wilton, who played Harriet Jones in episodes "Aliens of London" and "World War Three" of Doctor Who (2005), was offered a part in the original Doctor Who (1963) series as Lady Pienforte in the episode "Silver Nemesis". The part was taken by Fiona Walker.

Stephen Fry was set to write an episode for season 2 but due to budget constraints the episode was pushed back to season 3. The script was eventually canceled as Fry didn't have the time to rewrite the script to accommodate changes such as Rose's replacement Martha.

Richard Dawkins, who cameos as himself in Series 4's penultimate episode, is married to Lalla Ward, who had played one of the Doctor's previous companions, Romana, during Tom Baker's tenure and was also married to Tom Baker in the early 1980s.

Christopher Eccleston, largely unfamiliar with Doctor Who because he was never a fan of the original series, prepared for the role of the Doctor by watching the DVD of "The Talons of Weng-Chiang", a Tom Baker adventure originally broadcast in 1977.

Scottish Peter Capaldi has been allowed to keep his natural accent as the Doctor, the first non-English actor in the role to do so since Sylvester McCoy, who also spoke with his natural accent and was the first non-English actor to play the role.

Michael Grade, an outspoken critic of the original series for many years and the former BBC One controller who incurred the wrath of many fans when he took it off the air in 1985 for 18 months, admitted that he was completely won over by this revival of the series, which he described as "a classy, popular triumph for people of all ages and all backgrounds - real value for money for our licence fee payers".

The series is recorded on single camera video and then in post production it is 'filmised', a digital process designed to make it look like it was made on film. The process is so successful that even people who worked on the original series, such as director Christopher Barry and producer Philip Hinchcliffe, have mistakenly commented that the revived series is made on film.

David Tennant (who has become widely beloved for his performance as The Tenth Doctor) was the only actor considered for the role of the Tenth Doctor. Contrary to fan rumors, Chris Barrie, Bill Nighy and David Walliams were considered for the role of the Doctor, but not the Tenth Doctor.

One of the main differences in style from the original series, Doctor Who (1963), is that this series is recorded entirely on single camera, whereas studio scenes in the old series were usually recorded on multi-camera. This enables episodes of this series to be edited far better than the old series and allows directors to inject far more energy, pace and action into it. It also means that this series requires more time and money spent on recording it.

As of May 2014 37 actors have acted in both the original series and the new series. The first being William Thomas (Boomtown #1.11), and the most recent being Brian Millier Janet Henfrey and Christopher Villiers who both have guest roles in the first season with Peter Calpadi.

Despite quite a lot of new scenes being added to episodes in post production during the first series, all 13 episodes ran under the standard length of 45 minutes, so teaser trailers for the next week's episode were tacked on to bring the length up to standard. This has now become a staple of the show from 2005 onwards.

In 2011 David Tennant (who played the 10th Doctor) married Georgia Moffett, daughter of Peter Davison (who played the 5th doctor) Moffett herself had played the doctor's daughter on the show while Tennant was still on it.

Colin Baker, the sixth actor to play the Doctor in the original series during the 1980s, said he was ecstatic on hearing that Christopher Eccleston was cast as the Doctor, as he feared it would be very easy to cast someone in the role who just would not suit the part.

Russell T. Davies was sounded out to produce a revival of the series by the BBC One Controller of the time, Peter Salmon, in 1999. Although nothing came of this due to BBC Worldwide's desire to make a film version of the show, by late 2003 the new Controller of BBC One, Lorraine Heggessey, had persuaded Worldwide to surrender their film ambitions so that she could commission a new television version.

In the 50th anniversary special "The Day of the Doctor", it is revealed that there was an incarnation of The Doctor whom existed between The 8th (Paul McGann) and the 9th Doctor (Christopher Eccleston) called The War Doctor (John Hurt), this meant that the 11th Doctor (Matt Smith) was in reality the 13th Doctor, since The 10th Doctor has regenerated in "The Stolen Earth" (#4.12) and "Journey's End" (#4.13). If The Doctor had not regenerated into the 12th Doctor (Peter Capaldi) at the end of the 2013 Christmas special "Time of the Doctor" and had not gained a new regeneration cycle by the Time Lords, it would had ended with the demise of The Doctor. In the mythology of the show, Time Lords can only regenerate 12 times and only have 13 lives.

As of the 2013 Christmas Special, the only companion the Doctor told about his previous children (in a very brief remark) is Rose - his "daughter" from the fourth season notwithstanding as he was clearly a father before that episode.

Peter Capaldi is the 3rd Scottish actor to play The Doctor. Sylvester McCoy was the 7th Doctor and David Tennant was the 10th Doctor. Jamie McCrimmon (Frazer Hines) companion to the 2nd Doctor was the first Scottish companion and Amy Pond (Karen Gillan) companion to the 11th Doctor was the second Scottish companion. Karen Gillan was born in Inverness, Scotland in 1987.

After Steven Moffat became the Show-runner or Executive Producer, a decision was made to advance the Doctor's age which had been given for many regenerations as being 903. During the story "The Time of the Doctor" he was around 2000 years old and with the twelfth regeneration the age has been set as over 2000, as of the beginning of the eighth season.

The 50th anniversary special Day of the Doctor is also a prequel to Rose (#1.1), which we briefly glimpse The War Doctor (John Hurt) regenerate into The 9th Doctor (Christopher Eccleston), which happens just before The 9th Doctor meets Rose Tyler and saves her from the Autons.

Steven Moffat who succeeded Russell T. Davies as head writer and producer of the revived series, wrote The 11th Doctor's brief scene and first lines at the end of The End of Time - Part 2, but was uncredited.

Madame Kovarian, the main antagonist of Series 6 (Played by Frances Barber) was influenced by Emilio Largo, the main villain of the 1965 James Bond movie "Thunderball". Emilio Largo is the one-eyed member of the Spectre criminal organization. Madame Kovarian whom is one-eyed and was credited as "Eye Patch Lady" works for The Silence, which is a sinister relics order.

A new generation of fans and viewers and those unfamiliar with "Doctor Who", were confused about the concept of Regeneration and why The Doctor is played by different actors. For those unfamiliar with the series - when The Doctor's body is worn out and is mortally wounded and is near death. The Doctor undergoes a process called "Regeneration", which The Doctor is given a new body and a new face, which allows The Doctor to cheat death and go on living. Although The Doctor may look different, but he is the same character and the Regeneration also causes changes in The Doctor's character and his behavior. He still the same Time Lord, has the same memories and the same spirit. The Doctor does not pass away and he still lives and all the previous incarnations of The Time Lord live on in different time zones in space and time. In the show's mythology, The Doctor only has 12 regenerations which gives him only 13 lives, which at the end of his 13th life, The Doctor finally meets his end. But, in the 2013 Christmas Special Time of the Doctor, producer and head writer Steven Moffat decided to ignore the rules of Regeneration and The 11th Doctor (Matt Smith) who had used up all his regenerations and was in-reality in his 13th and final incarnation, was given a new Regeneration cycle by the Time Lords and The Doctor is now in his 14th incarnation and is played by Peter Capaldi.

Christopher Eccleston was originally to opposite David Tennant and Matt Smith in the 50th anniversary special The Day of the Doctor. When Eccleston declined, Steven Moffat replaced the 9th Doctor with a new character, The War Doctor (John Hurt) revealed as an incarnation of The Doctor that existed between the 8th (Paul McGann) and the 9th Doctor (Christopher Eccleston), whom fought in the Time War. At the end, The War Doctor is seen regenerating into The 9th Doctor and John Hurt is briefly glimpsed regenerating into Christopher Eccleston.

Captain Jack, introduced in the first series, was the first openly non-heterosexual character in the history of televised Doctor Who. A homosexual subplot suggested by Ian Briggs between two characters in the 1989 serial "The Curse of Fenric" had been vetoed as unsuitable for a family audience.

Donna Noble meeting River Song in River Song's 2-part debut Silence of the Library (#4.8) and Forest of the Dead (#4.9) was a foreshadowing. The 11th Doctor's companion Amy Pond has red hair and later revealed to be River Song's own mother in A Good Man Goes to War (#6.7). Both Catherine Tate (Donna Noble) and Karen Gillan (Amy Pond) are natural redheads.

While Doctor Who is generally considered to have run for over fifty years, the classic series was cancelled in 1989. Despite the 2005 series being a continuation of the 1963 series, they are technically two different programs, making for less than fifty years of onscreen stories, despite the classic series premiering over fifty years ago, in 1963.

In real life, David Tennant (The 10th Doctor) dated Sophie Myles (Madame de Pompadour) and later married Georgia Moffett (Jenny). Madame de Pompadour died at the end of The Girl in the Fireplace (#2.4) and at the end of The Doctor's Daughter (#4.6) Jenny dies from a fatal gunshot wound, but is revived.

When Georgia Moffett was interviewed about The Doctor's Daughter (#4.6), Georgia Moffett asked her son Tyler who is his favorite Doctor, which Tyler revealed as David Tennant (The 10th Doctor) because he runs so fast. When Georgia Moffett married David Tennant, Tennant adopted her son and his name was changed from Tyler Moffett to Ty Tennant.

Because of the varying technical and logistical demands of the 13 episodes of the first series, filming was broken into five production blocks. Episodes 1, 4 and 5 formed block one, and was filmed between July and September 2004. Block 2 comprised episodes 2 and 3, and was filmed between September and October 2004. Block 3 contained episodes 6 and 8 filmed between October and December. Block 4 was split into two sub blocks, 4A and 4B due to the large visual effects demands of episode 7 which on its own became block 4A, filmed between December 2004 and January 2005. Episodes 9 and 10 made up Block 4B, filmed from December through February 2005. Episodes 11-13 formed Block 5 filmed from February until March 2005.

Series 4 had a recurring theme ("Prediction"). In The Fires of Pompeii (#4.2)The Sybilline Sisterhood are a cult of soothsayers. Evelina predicts truths about The Doctor and Donna (their real names) and that Donna has something on her back (A Time Beetle). In Planet of the Ood (#4.3) Ood Sigma tells The Doctor that his song will end soon (The Tenth Doctor's regeneration into the Eleventh Doctor) and in Turn Left (#4.11) Donna meets a fortune teller who shows Donna what her life could had been if she had never met The Doctor and a Time Beetle attachés itself onto Donna's back (Which Evaline predicted).

The choice of Russell T. Davies to write and produce the series surprised some commentators, as he was most famous for writing the explicit and uncompromising adult drama about homosexual men in Manchester, Queer as Folk (1999).

The Soothsayer, Karen Gillan played in The Fires of Pompeii in Series 4, was not considered by Steven Moffat, to be a ancestor of The Eleventh Doctor's companion Amy Pond, whom Karen Gillan played 2010 - 2012.

The death of Jenny (Georgia Moffett) and The Doctor's speech which he makes to the humans and the Hath in The Doctor's Daughter (#4.6) was strongly influenced by 2000's "Gladiator". The speech Lucilla makes to the Roman spectators and the Roman Centurions and the Gladiators, when General Maximus dies.

The fate of the 8th Doctor was not revealed on-screen until the mini-episode Night of the Doctor, which is a prequel to the 50th anniversary special Day of the Doctor and Rose (#1.1). It was assumed by fans that The 8th Doctor (Paul McGann) fought in the Time War and was wounded and regenerated into The 9th Doctor (Christopher Eccleston). The mini-episode revealed The 8th Doctor is killed in a spaceship crash and was temporarily revived and given a potion that regenerated him into The War Doctor (John Hurt), so he can return to Gallifrey and fight in the Time War.

The identity of The Woman (Clare Bloom) whom mets Wilfred Mott in the "End of Time" has never been confirmed onscreen, however show runner Russell T Davies confirmed in interviews that she is supposed to be the Doctor's mother. Other fan theories were that she was the Doctor's former companion Romana, or the Doctor's granddaughter Susan.

Sarah Louise Madison who played a Weeping Angel throughout the Matt Smith era from The Time of Angels (#5.4) to The Time of the Doctor, also played a Time Zombie in Journey to the Center of the TARDIS (#7.11).

Christopher Eccleston expressed interest in appearing as the 9th Doctor in the 50th anniversary special The Day of the Doctor, however after meeting with Steven Moffat he ultimately was not able to be involved. Reportedly this was either due to scheduling issues, or the fact Eccleston was unwilling to sign up without first reading a script, which Moffat had not finished writing at that time.

Some of the cast went on to star in films based on Marvel comics. Christopher Eccleston played Malakith in 2013's "Thor: The Dark World". Jenna Coleman played Connie in 2011's "Captain America: The First Avenger" and Karen Gillan played Nebula in 2014's "Guardians of the Galaxy". David Tennant will play villain The Purple Man in 2015's "aka Jessica Jones."

In the original series. Leela (Louise Jameson) companion of The 4th Doctor (Tom Baker) had left at the end of The Invasion of Time: Part Six (#15.26), and decided to discontinue traveling with The Doctor to stay on Gallifrey, when she fell in love with Commander Andred. It had been believed by fans that Leela had fought and died in the Time War. It was revealed in the audio productions of "Doctor Who", Leela had survived the destruction of Gallifrey and had been captured by the N'Zai. The N'Zai tortured Leela for information on Leela and Leela later died in the N'Zai prison. However, Louise Jameson had been rumored to appear opposite Tom Baker in the 50th anniversary special, but the rumor was false.

In the books and audio productions, The Doctor in his 4th, 7th and 10th incarnations, met Boudica, warrior queen of the Iceni tribe. In the William Hartnell story The Romans, The 1st Doctor and Vicki met Emperor Nero, whom Boudica led her tribe in rebellion against and Alex Kingston (River Song) has played Boudica in the 2003 film, which Frances Barber (Madame Kovarian) also starred as Agrippina.

In the original outline of Robot of Sherwood (#8.3). The Headless Monks, whom made their first and only appearance of A Good Man Goes to War (#6.7) were working with the Sheriff of Nottingham, whom The Sheriff had formed an alliance with and The Doctor and Clara set out to convince Robin Hood to form a band of outlaws to fight back against The Sheriff and The Headless Monks.

It was rumored that there was going to be an episode in Series 8 called "The Ghosts of Pompeii" which was to be a sequel story to The Fires of Pompeii (#4.2), which was Peter Capaldi's debut, which he had played a different character prior to being cast as the 12th Doctor.

Billie Piper had been rumored to appear opposite David Tennant as Rose Tyler in the 50th anniversary special. However, Billie Piper did appear in the 50th anniversary special as The Moment, also known as The Galaxy Eater. An ancient Gallifreyan doomsday weapon which The War Doctor uses to destroy Gallifrey, but The Moment appears in the form of Rose Tyler/Bad Wolf and allows The War Doctor to meet the 10th and 11th Doctor and convinced The War Doctor to work with his future incarnations and prevent the destruction of Gallifrey.

When Steven Moffat took over from Russell T. Davies as the showrunner. Steven Moffat wanted the series to be told from Amy Pond's point of view and wanted the series to be like a fairy tale. Amy Pond goes with her imaginary childhood friend The Doctor whom she nicknames The Raggedy Doctor and goes with him in his magic police box The TARDIS on a magical adventure across time and space.

River Tam the protagonist from "Firefly" and its sequel film "Serenity" is believed by some fans to have been an influence behind River Song. River Song (As Melody Pond) is conditioned and trained as an assassin to kill The Doctor. When she was place in Father Octavian's custody, after being imprisoned for The Doctor's murder, River escaped from the Banzantium spaceship and escapes aboard the TARDIS.

Lara Croft, the main protagonist of the video game "Lara Croft: Tomb Raider" is a strong influence behind River Song. Like Lara Croft, River Song is a archaeologist and also like Lara Croft, River Song is known for using a gun.

David Tennant became the 4th actor from the series to appear in the cinematic Marvel comic universe and on 27 January 2015, David Tennant was announced to be starring as Kilgrave in the Marvel comic film "A.K.A Jessica Jones". Jenna Coleman starred in "Captain America: The Winter Solider", Christopher Eccleston starred in "Thor: The Dark World" and Karen Gillan starred in "Guardians of the Galaxy".

In the Battle of Zaruthstra in A Good Man Goes to War (#6.7) which took place on the planet Zaruthstra in the year 4037, which Strax (Dan Starky) was a nurse of the battlefield. The human inhabitants of that world wear 19th century British clothing.

The cinema introductions of Strax the Sontaran and the 10th and 11th Doctor of the 50th anniversary special of "Doctor Who" were not featured in the special features of the 50th anniversary special DVD release.

To celebrate the 50th anniversary special, and to combat his disappointment at not being given a role in it, Peter Davison (The 5th Doctor) made his own amateur webisode anniversary special. The short webisode (which Davison wrote and directed and his daughter produced) starred his friends and relatives, with many former Doctor Who actors making cameo appearances. The plot revolves around Peter Davison, Colin Baker and Sylvester McCoy trying to sneak into the set of the 50th anniversary special, when Steven Moffat declines to cast them.

In Last of the Time Lords (#3.13) Captain Jack Harkness reveals to The Doctor and Martha that he was nicknamed "The Face of Boe", leading The Doctor and Martha to believe that Jack *is* The Face of Boe, the gigantic humanoid head The Doctor, Rose and Martha had encountered on New Earth and Captain Jack grew up in a Earth colony on the Boeshane peninsular. If Captain Jack is indeed The Face of Boe, it's most likely that in the far future, Captain Jack underwent a genetic mutation and mutated into his new incarnation - The Face of Boe.

In David Tennant's farewell episode The End of Time - Part 1 and 2, the evil Lord President of the Time Lords (Timothy Dalton) is revealed as Rassilon, the founder of Time Lord society. In The Five Doctors, The 2nd Doctor tells Brigadeer Lethbridge-Stewart that there was a rumor that the Time Lords had rebelled against his cruelty and imprisoned him in the Black Tower (Rassilon's final resting place). In the back-story of Rassilon's appearance in the 2-part special, Rassilon was brought back from the dead to lead the Time Lords in the Last Great Time War. But, The War Doctor foiled Rassilon's plot to use The Tear of Isha to wipe out The Daleks from the Tantalus Eye and had condemned The Doctor as an enemy of The Time Lords and had planned to save Gallifrey from destruction by using the Ultimate Sanction turn the Time Lords into beings of pure consciousness, only to be time-locked by The Doctor.

In the back-story of Madame Kovarian (Frances Barber) the main antagonist in Series 6: Madame Kovarian was a member of the Papal Mainframe space church, which Tasha Lem (Orla Brady) is the Mother Superior, but left the Papal Mainframe and became a servant of the Silence religious order.

If the series had indeed been a reboot and not a direct sequel to the original series that aired from 1963 - 1989 and the 1996 TV movie and it would have disregard the original series and the TV movie as if they had never happened. Christopher Eccleston would had been the first incarnation of The Doctor and instead of The Doctor leaving Gallifrey to explore time and space because he was bored, by stealing the TARDIS, he would begin his adventures across time and space by escaping in the Tardis, when Gallifrey is destroyed in the Time War along with the Time Lords. Rose Tyler (Billie Piper) would had been his first companion to travel him in the Tardis and The Doctor would had encountered The Daleks before and revealed to be the race of aliens that the Time Lords fought in the Time War, when Gallifrey was destroyed. Christopher Eccleston regeneration into David Tennant at the end of the first season would had been The Doctor's first regeneration, with Matt Smith as the 3rd Doctor and Peter Capaldi as the 4th Doctor.

A group on the Facebook social network called 'Should Summer Glau have a guest role in a episode of Doctor Who?' was set up as an online petition, so American actress Summer Glau can appear in an guest role in a future season of the show. Summer Glau is best known for her roles in the science fiction TV shows "Firefly" and "Terminator: The Sarah Connor Chronicles". Matt Smith (The 11th Doctor) later went on to star in "Terminator: Genysis".

Matt Smith (The Eleventh Doctor) later went on to star opposite Arnold Schwarzenegger in 2015's "Terminator: Genysis". In the series, The Doctor is known for fighting against the Dalek and Cybermen robots.

It was rumored Sophia Myles whom played Madame de Pompadour in Series 2's The Girl in the Fireplace (#2.4) to replace Karen Gillan as the new companion in Series 7. Steven Moffat denied the rumor, stating that Sophia Myles's return in the series as The Doctor's new companion would be inappropriate and Jenna Coleman was officially announced as the new companion Clara Oswald.

In the original series, Leela (Louise Jameson) companion of the Fourth Doctor (Tom Baker) remained on Gallifrey, when she fell in love with Commander Andred (Chris Tranchell). It was assumed, Leela fought in the Time War and died. In the audio productions, Leela had survived the destruction of Gallifrey and had been captured and tortured by the Z'Nai, for information about Gallifrey and Leela died in the Z'Nai prison.

David Tennant (The 10th Doctor) dated Sophie Myles, whom played Madame De Pompadour in The Girl in the Fireplace (#2.4). David Tennant later married Georgia Moffett who played Jenny in The Doctor's Daughter (#4.6).

Peter Capaldi had played a time traveler before. Peter Capaldi appeared opposite Alexei Sayle in "Drunk in Time", a parody of the classic 1960s science fiction series "Lost in Time" in "The All New Alexei Sayle" show in 1995. Alexei Sayle played DJ in the 1985 Colin Baker story Revelation of the Daleks.

Alexei Sayle whom played DJ in the 1985 Colin Baker story Revelation of the Daleks would later appear opposite future Doctor Peter Capaldi in "Drunk in Time", a parody of the 1960s science fiction series "Lost in Time" in Sayle's BBC sketch comedy show "The All New Alexei Sayle Show".

In The Invasion of Time: Part Six (#15.26) in the original series. Borusa is seen reading a newspaper about the 1912 Titanic disaster, which the 4th Doctor claimed he had nothing to do with it. In Rose (#1.1) Rose Tyler is shown an old photo of The 9th Doctor with a family in 1912 and is told that The 9th Doctor told the family not to go aboard the Titanic and that the family survived. In the 2007 Christmas Special Voyage of the Damned (#4.0) The 10th Doctor goes aboard the Sto passenger spaceship, which is named after the Titanic passenger liner that sunk in 1912.

In one of River Song's diary entries, The Doctor and River Song went to a picnic on Asgard. Christopher Eccleston starred as the main antagonist Malakith in 2013's "Thor: The Dark World", based on the Marvel comic which was based on the Viking Norse myth of Thor the God of Thunder.

The Moment whom The War Doctor meets and which The War Doctor can only see and hear and shows him his future by allowing The War Doctor to meet his future incarnations and convinces him to work with his future incarnations and prevent the destruction of Gallifrey was strongly influenced by "A Christmas Carol" by Charles Dickins.

Spoilers

The trivia items below may give away important plot points.

In each series, there is an underlying story arc that pans all episodes until finally fully addressed in the season finale. For Series 1, it is the concept and identity of the Bad Wolf. Series 2, the Torchwood Institute. Series 3, the identity of Mr. Saxon. In series 4, there are several little references and jokes that eventually lead to the plot of the finale, including the missing planets and the bees disappearing from Earth, and repeated appearances of Rose Tyler on screens and monitors. In addition, there are repeated references to there being something on Donna's back. While this does not carry on to the series finale itself, it does play an important part in the episode which sets up the finale's story. In series 5, there are "cracks" in the universe, which must ultimately be fixed in the series finale. In series 6, a future version of the Doctor is seen to be killed, causing complications for the "present" version of the Doctor and his companions, also there is the repeated appearance of Madame Kovarian who only Amy can see. Series 7 revolves around the "impossible" Clara Oswin Oswald, whom the Doctor keeps running into in various places and times, though she does not remember him.

In Series 8 The Doctor's arch foe, The Master, is first introduced to audiences as Missy (played by Michelle Gomez) as a completely new character, before she is revealed to be the newest incarnation of the villainous Time Lord. This is keeping with tradition, as twice previously a new character is introduced, only to be revealed as The Master's newest body. In "The Keeper of Traken", Anthony Ainely portrays the kindly Professor Tremas for a full serial before he is possessed by The Master, and in "Utopia", Professor Yana (played by Derek Jacobi) is revealed in the final act as The Master by way of the Chameleon circuit.